The present invention relates in general to the sealing of an interface between two or more members, such as between a container body and a container spout. More specifically, but not exclusively, the present invention concerns sealing mechanisms, structures, and techniques to be used in combination with liquid-storage containers which may be used to store (and dispense) various liquid substances such as paint, household cleaners, laundry products, and beverages, to name a few.
Liquid storage containers have been used to store and dispense a wide variety of liquids. While the use of a pouring spout as part of a liquid-storage container is now commonly used for liquid laundry detergents and fabric softeners, only recently have these types of containers been adapted to other liquid-product containers, in particular paint containers. Typical metal paint cans include a generally cylindrical can body with a circular upper opening surrounded by a generally U-shaped peripheral channel which captures the outer peripheral lip or protrusion of a circular lid. A wire-like metal handle is provided and hinged at opposite ends to the paint can body. Anyone who has done any painting using such a paint can is no doubt familiar with the many problems in the sense of wasted and splattered paint. The awkwardness of pouring paint from the can into a tray for a roller is also seen as a drawback with this particular design. Dipping a paintbrush into the can and then using the can edge as a wiping edge also creates a mess and causes paint to be deposited in the annular U-shaped channel. As paint collects in this peripheral channel, resealing the lid becomes particularly messy as the captured paint is pushed out and may either splatter or run down the side of the paint can. Aside from the mess, the current metal paint can design results in wasted paint, not only from what drips, splatters, or runs down the side of the can, but also from not being able to tightly reseal the lid onto the can body. If the lid is not tightly resealed on the can body, the paint can dry out or skim over, causing obvious problems of continued use and often resulting in the leftover portion of paint being discarded.
By designing a paint container with a screw-on lid and a pouring spout with an excess paint drain-back feature, a number of the disadvantages with metal paint cans and the use of such cans can be eliminated. While plastic containers with spouts are now in use for laundry products, there are a number of reasons why such containers are not suitable for paint and why significant design changes must be invented to be able to create a suitable paint container with these structural features. For example, the size of the opening in the container body needs to be expanded for a paint container as compared to a liquid laundry detergent and, as such, the spout design must change. As this occurs, the sealing mechanisms or structures have to be considered. There is a desire to have a wiping edge for the paintbrush as part of a suitable paint container, a factor which is not a consideration with a liquid laundry detergent. The attempt to incorporate this type of wiping edge as part of the pouring spout presents additional design challenges. The drain-back feature is also an important part of any new and improved paint container. Any paint which is wiped off the brush or drips from the brush and any paint which might run down the lip of the pouring spout needs to have a path to reenter the body of the paint container.
A further consideration for a suitable paint container is the overall shape and balance, not only for handling and transporting convenience, including the possibility of stacking, but also for the practical consideration of being able to tint to a particular color by adding pigment to a base color, such as white. This tinting requires access to the interior of the paint container body and also requires some type of vibratory shaking of the paint container. This in turn focuses some attention on the design in terms of the size and shape of the container as well as the design of the sealing mechanisms which are employed as part of the paint container at those interfaces where leakage could conceivably occur.
In developing such containers, the costs and difficulties associated with manufacturing the containers is always a concern. One manufacturing issue relates to the ability to maintain the position of the seal between the container and the spout during assembly. As mentioned before, the seal between the pouring spout and the container must survive a number of drastic conditions, including vibratory shaking. In one type of design, an o-ring seal or gasket is used to seal between the spout and the container. During assembly, the seal is rolled up around a frustum-shaped sidewall of the spout that extends within the container so that the seal is positioned at the lip of the container. As the seal rolls up the frustum-shaped wall, the seal stretches and twists, which in turn pre-loads the seal. As a result, the seal is biased to roll back down towards the narrower part of the wall, away from the lip of the container. With the seal out of position, leakage between the spout and the container can occur, which can be extremely undesirable with liquids like paint.
Thus, there is a need for improvement in this field.